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Java > Open Source Codes > smallsql > database > ExpressionFunctionRound


1 /* =============================================================
2  * SmallSQL : a free Java DBMS library for the Java(tm) platform
3  * =============================================================
4  *
5  * (C) Copyright 2004-2006, by Volker Berlin.
6  *
7  * Project Info: http://www.smallsql.de/
8  *
9  * This library is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU Lesser General Public License as published by
11  * the Free Software Foundation; either version 2.1 of the License, or
12  * (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17  * License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with this library; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
22  * USA.
23  *
24  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25  * in the United States and other countries.]
26  *
27  * ---------------
28  * ExpressionFunctionRound.java
29  * ---------------
30  * Author: Volker Berlin
31  *
32  */
33 package smallsql.database;
34
35
36 final class ExpressionFunctionRound extends ExpressionFunctionReturnP1Number {
37
38     final int getFunction(){ return SQLTokenizer.ROUND; }
39
40     boolean isNull() throws Exception JavaDoc{
41         return param1.isNull() || param2.isNull();
42     }
43     
44
45     final double getDouble() throws Exception JavaDoc{
46         if(isNull()) return 0;
47         final int places = param2.getInt();
48         double value = param1.getDouble();
49         long factor = 1;
50         if(places > 0){
51             for(int i=0; i<places; i++){
52                 factor *= 10;
53             }
54             value *= factor;
55         }else{
56             for(int i=0; i>places; i--){
57                 factor *= 10;
58             }
59             value /= factor;
60         }
61         value = Math.rint( value );
62         if(places > 0){
63             value /= factor;
64         }else{
65             value *= factor;
66         }
67         return value;
68     }
69     
70
71 }
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